When Carrie Fagerstrom was looking for a new home in Portland, her must-have list didn't include a spacious yard, plenty of closets or even a large kitchen.

Her highest priority: the comfort of her cats.

"I really wanted a house that would allow me to build a place for them," said Fagerstrom, who had visions of a catio out back.

Catio tour

The Feral Cat Coalition of Oregon and the Audubon Society of Portland will once again offer a Catio Tour to offer inspiration for those looking for ways for their cats to have safe outdoor time. The date has yet to be announced.

A catio is essentially a cat's playground. It's an enclosed, covered area, much like a patio, that allows feline friends to be exposed to the outdoors, getting fresh air and scenery, while keeping them safe from predators.

"I thought it would be as simple as running wire on three sides and putting tarp overhead, but it wasn't that easy," Fagerstrom said. "It ended up being a much bigger project, but I love it."

Roughly $5,000 later, her eight cats have room to roam in a catio filled with scratching posts, climbing apparatuses and even a drinking fountain. The 11-foot-tall space also contains human seating so that Fagerstrom and her friends can enjoy it as well.

"It's a very calm and serene place," she said.

Catios got their start with cat breeders and at animal sanctuaries, but more and more cat owners have begun building them at home, according to Kate Benjamin, founder of Hauspanther.com, an online magazine for design-conscious cat people.

"I've been seeing a lot more people catifying their homes," Benjamin said. "If your cats are truly beloved members of your family, you won't let them live outside. There are just too many threats."

"An indoor cat is more likely to be protected from injury, such as that from road traffic accidents and neighborhood cats, as well as less likely to contract infectious diseases that are passed from cat to cat," Ellis said. "However, an indoor-only cat may be more likely to experience boredom and frustration from the inability to exhibit hunting behaviors, running and exploring."

That's why catios are great, said Fresno, Calif. resident Harvie Schreiber. The two catios she and her husband built onto their home give their four cats the best of both worlds, she said.

"We have indoor cats only and we believe they live longer, healthier, safer lives, but we wanted to give them a chance to enjoy the outdoors in a safe way," she said.

The Schreibers started by turning the small patio off their bedroom into a catio. Heavy-duty wiring was used to enclose the space, which already had a roof. They added some cat favorites like trees and cardboard boxes, and the area became a favorite spot for their feline family members.

That's when the Schreibers knew they wanted to build a larger catio, off the main living area in their home and overlooking the backyard pool.

Since it was so visible and centrally located, they wanted the catio to be attractive as well as functional.

Harvie Schreiber had the entire thing, including the ceiling, painted Tree Frog Green. She hung decorative artwork and included a couch for humans. The catio also has a 7-foot-tall cat condos and tons of toys.

The cats "love being out there and getting the fresh air," Schreiber said. "Even when it's horribly hot in the summer and freezing cold in the winter, they still want to be out there."

Tips on building a catio:

A catio can be built in any home, no matter the size. While some people build large, elaborate ones, a small window enclosure also will work if you're short on space.

Make sure the catio is fully enclosed, so cats cannot get out and predators cannot get in.

Provide cats a view of the outdoors, and make sure there's ventilation so that fresh air comes in. Be aware of the weather: You might need a fan in the summer or a heater in the winter.

Include plenty of toys and features your cats enjoy, such as climbing shelves, scratching posts, cat condos, trees or a water fountain.

Keep their litter box in the catio.

Make the space pleasant for humans too. Include comfortable seating so you and your cats can enjoy the catio together.